Hydrogen - a very special type of gas

The Fuel of the Future, or Futuristic Looking Fuel?

One of the most interesting, and in some ways promising, alternative
transportation
fuels is hydrogen. While only experimental vehicles are operating on
this fuel now,
the potential for this unique energy source is excellent. Anyone who
has taken a
chemistry class knows that hydrogen is number one on the periodic
chart of elements
and the lightest of all elements. It is easy to produce through
electrolysis, simply
splitting water (H20) into oxygen and hydrogen by using
electricity. However, these
days, nearly all hydrogen is made from natural gas.

Because hydrogen burns nearly pollution-free, it has been looked at
as the ultimate
clean fuel. When burned, it turns into heat and water vapor. When
burned in an internal
combustion engine (the kind of engine in gasoline cars today), the
combustion also
produces small amounts of other gases. These other gases are mostly
oxides of nitrogen
because the hydrogen is being burned with air, which is about
two-thirds nitrogen.
Being a non-carbon fuel, the exhaust is free of carbon dioxide.
Carbon dioxide, emitted
from our burning of fossil fuels, is causing the world's climate to change.

Hydrogen is normally a gas and can be compressed and stored in
cylinders. The main
problem with hydrogen is bulk of the cylinders (fuel tanks).
Compressed hydrogen
contains less energy per volume compared to liquid fuels like
gasoline or ethanol.
Hydrogen can also be cooled to produce liquid hydrogen, but it is costly.

Hydrogen's clean burning characteristics may, one day, make it a
popular transportation
fuel. For now, the problem of how to store enough hydrogen on a
vehicle for a reasonable
range, and its high cost, compared to gasoline, are critical barriers
to widespread
commercial use.

Nearly all hydrogen currently is made from natural gas. For that
reason, hydrogen
usually costs more than natural gas.

Hydrogen fueled vehicles
There have only been a small number of prototype hydrogen vehicles made. Most
of these have been experimental vehicles made by car manufacturers.
Nearly all of
these prototype cars were equipped with internal combustion engines,
similar to ones
that run on gasoline.

Hydrogen is also used in fuel cells. See the discussion on this in
the fuel cell vehicle section below.